Evolution of strength and structure during SPD processing of Ti-45Nb alloys: experiments and simulations

摘要

A β-phase Ti-45Nb alloy was processed by several severe plastic deformation (SPD) methods as highpressure torsion, cold rolling and folding, and hydrostatic extrusion to enhance its strength by achieving an ultrafine grained structure without affecting the Young's modulus being close to that of bone material. Mechanical properties during processing were monitored by direct torque and Vickers hardness measurements, while the micro-anostructural evolution was investigated by transmission electron microscopy and X-ray line profile analysis. Simulations of both mechanical and micro-ano-structural data were performed on the basis of the SPD work-hardening model by Zehetbauer. The simulations not only found a good agreement with the deformation-specific evolution of strength and density of individual dislocations but also well reflected mesoscopic structural quantities such as the sizes of cell/grain interiors and walls without introducing additional fitting parameters.